Fuel cell elements within a solid oxide fuel cell (SOFC) stack are made up of either planar or tubular elements which are stacked together in racks, One problem with such racks is the seals which separate fuel and oxidant compartments. Another problem is the electrical connections which must be made to the cells. Usually these two issues of sealing and electrical connection are solved separately. For example a standard planar stack described by de Haart et al, SOFC VII, eds. Yokokawa & Singhal, Electrochemical Society, Pennington N.J., 2001, p. 111-119 is sealed with glass around the plate edges while the electrical connection is made with metallic interconnect plates. Similarly in a Westinghouse design of tubular stack, the seal is made with a closed end tube into which an air feeder pipe extends, while the electrical connection is made using nickel mesh connectors outside the tubes. In U.S. Pat. No. 5,827,620, a small diameter tubular cell is sealed by a rubber joint at the cold end of the tube, whilst the electrical connection is made via wires passing inside and outside the tubes.
For their operation, fuel cells use gaseous consumables in the form of fuel and oxidant. Thus one gaseous consumable is an oxidant, for example oxygen or air, supplied to a cathode of the cell. Another gaseous consumable is the fuel, for example hydrogen or one or more compounds from which hydrogen can be obtained, supplied to an anode of the cell.